U.S. patent application number 13/718026 was filed with the patent office on 2014-06-19 for hoist limiting systems and methods.
This patent application is currently assigned to LONGYEAR TM, INC.. The applicant listed for this patent is LONGYEAR TM, INC.. Invention is credited to JOSHUA BYRON, STEFAN WREDE, CHRIS WRIGHT.
Application Number | 20140166953 13/718026 |
Document ID | / |
Family ID | 50929864 |
Filed Date | 2014-06-19 |
United States Patent
Application |
20140166953 |
Kind Code |
A1 |
WRIGHT; CHRIS ; et
al. |
June 19, 2014 |
HOIST LIMITING SYSTEMS AND METHODS
Abstract
A hoist rotation limiting system for a hoist. A hoist drum has a
grooved exterior surface configured to position a cable in a
predetermined position relative to the ends and longitudinal axis
of the hoist drum as the cable is wound onto or off of the hoist
drum. Upon the cable being positioned in the predetermined
position, the cable urges portions of a carrier weldment to contact
a switch, thereby sending an electrical signal to stop rotation of
a hoist motor.
Inventors: |
WRIGHT; CHRIS; (Ontario,
CA) ; WREDE; STEFAN; (Kirchhundem, DE) ;
BYRON; JOSHUA; (South Jordan, UT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
LONGYEAR TM, INC. |
South Jordan |
UT |
US |
|
|
Assignee: |
LONGYEAR TM, INC.
South Jordan
UT
|
Family ID: |
50929864 |
Appl. No.: |
13/718026 |
Filed: |
December 18, 2012 |
Current U.S.
Class: |
254/270 |
Current CPC
Class: |
B66D 1/56 20130101 |
Class at
Publication: |
254/270 |
International
Class: |
B66D 1/56 20060101
B66D001/56 |
Claims
1. A hoist limiting system for a hoist having a hoist motor, the
hoist limiting system comprising: a hoist drum coupled to the hoist
motor, wherein the hoist drum is configured for selective rotation
about a rotation axis, wherein an exterior surface of the hoist
drum defines a groove, and wherein the hoist drum has a first end
and a second end; a cable configured to be positioned therein the,
groove of the hoist drum, wherein the cable is at least partially
wound around the hoist drum such that, upon rotation of the hoist
drum about the rotation axis in a first direction, the cable is
further wound around the hoist drum in a predetermined direction
relative to the first and second ends of the hoist drum; a carrier
weldment positioned adjacent the hoist drum and comprising: a
mounting plate slidably attached to the hoist, at least one trigger
contacting member extending away from a first side of the mounting
plate a predetermined distance; and at least one cable contacting
finger attached to and extending away from a second, opposed side
of the mounting plate; a mounting bracket fixed to a central
portion of a frame of the hoist; and at least one switch positioned
on a central portion of the mounting bracket between the hoist drum
and the mounting plate, the at least one switch being electrically
coupled to the hoist motor, wherein the at least one switch is
located interior to the at least one trigger contacting member, and
wherein after the cable is wound around the hoist drum a
predetermined distance, a portion of the cable contacts the at
least one cable contacting finger and urges the at least one cable
contacting finger, the mounting pate, and the at least one trigger
contacting member to slide towards an end of the hoist drum,
wherein upon sliding a predetermined distance, the at least one
trigger contacting member contacts and actuates the at least one
switch, and wherein upon actuation, the at least one switch sends a
signal to the hoist motor to alter rotation of the hoist motor arid
hoist drum.
2. The hoist limiting system of claim 1, wherein the groove is a
continuous, helical groove extending from the first end of the
hoist drum to the second end.
3. The hoist limiting system of claim 1, wherein a longitudinal
axis of the at least one cable contacting finger is substantially
normal to the rotation axis of the hoist drum.
4. The hoist limiting system of claim 3, wherein a longitudinal
axis of the at least one trigger contacting member is substantially
normal to the rotation axis of the hoist drum.
5. The hoist limiting system of claim 1, wherein the carrier
weldment further comprises at least one rod attachable to the
hoist, and wherein a longitudinal axis of the at least one rod is
substantially parallel to the drum rotation axis of the hoist
drum.
6. The hoist limiting system of claim 5, wherein at least a portion
of the mounting plate is slidably attached to the at least one
axial rod so that the mounting plate can slide in a direction
substantially parallel to the rod longitudinal axis.
7. The hoist limiting system of claim 6, farther comprising a means
for centering at least a portion of the mounting plate relative to
a center of the hoist drum.
8. The heist limiting system of claim 7, wherein the means for
centering comprises a spring positioned on opposed ends of the at
least one axial rod.
9. The hoist limiting system of claim 1, wherein the at least one
switch comprises at least a first switch and a second switch,
wherein the first switch sends a first electrical signal to the
hoist motor upon actuation by the trigger contacting member moving
in first direction, and the second switch sends a second electrical
signal upon actuation by a trigger contacting member moving in a
second direction.
10. The hoist limiting system of claim 1, further comprising means
for positioning at least a portion of the cable around the hoist
drum in a repeatable manner.
11. The hoist limiting system of claim 1, wherein the signal to
alter rotation of the hoist motor and hoist drum comprises a signal
to stop the rotation of the hoist drum.
12. The hoist limiting system of claim 1, wherein the signal to
alter rotation of the hoist motor and hoist drum comprises a signal
to slow down rotation speed of the hoist drum.
13. The hoist limiting system of claim 1, wherein the signal to
alter rotation of the hoist motor and hoist drum comprises a signal
to reverse the rotation direction of the hoist drum.
14. A method for limiting the rotation of a hoist beyond a desired
amount, the method comprising: providing a cable at least partially
wound around a hoist drum of a hoist, wherein an exterior surface
of the hoist drum defines a groove configured to receive a portion
of the cable therein; slidably attaching a mounting plate to a
mounting bracket attached to a frame of the hoist, wherein at least
one trigger contacting member extends away from a first side of the
mounting plate a predetermined distance and wherein at least one
cable contacting finger extends away from a second, opposed side of
the mounting plate; providing at least one switch positioned on a
central portion of the mounting bracket between the hoist drum and
the mounting plate, the at least one switch being electrically
coupled to the hoist motor, selectively rotating the hoist drum in
a first direction about a rotation axis such that the cable is
wound onto the hoist drum and a portion of the cable contacts the
at least one cable contacting member, wherein upon contacting the
at least one cable contacting member, the portion of the cable
urges the at least one cable contacting finger, the mounting plate,
and the at least one trigger contacting member to slide towards an
end of the hoist drum, wherein upon sliding a predetermined
distance, the at least one trigger contacting member contacts and
actuates the at least cite switch, and wherein upon actuation, the
at least one switch sends a signal to the hoist motor to stop
rotation of the hoist motor and hoist drum.
15. A hoist limiting system for a hoist having a hoist motor, the
hoist limiting system comprising: a hoist drum coupled to the hoist
motor, wherein the hoist drum is configured for selective rotation
about a rotation axis wherein the hoist drum has a first end and a
second end; a cable configured to be positioned around the hoist
drum wherein be cable is at least partially wound around the hoist
drum such that, upon rotation of the hoist drum about the rotation
axis in a first direction, the cable is further wound around the
hoist drum in a predetermined direction relative to the first and
second ends of the hoist drum; a carrier weldment slidably
positioned adjacent the hoist drum and comprising a mounting plate
slidably attached to the hoist; a mounting bracket fixed to a
central portion of a frame of the hoist; and at least one switch
positioned on a central portion of the mounting bracket between the
hoist drum and the mounting plate, the at least one switch being
electrically coupled to the hoist motor, and means for positioning
at least a portion of the cable around the hoist drum in a
repeatable manner. wherein the at least one switch is located
interior to the at least one trigger contacting member, and wherein
upon the cable being wound around the hoist drum a predetermined
distance, a portion of the cable contacts the carrier weldment and
urges the carrier weldment into contact with the at one switch, and
wherein contact with the carrier weldment actuates the at least one
switch to send a signal to the hoist motor to alter rotation of the
hoist motor and hoist drum.
16. The hoist limiting system of claim 15, further comprising a
means for centering at least a portion oft he carrier weldment
relative to a center of the hoist drum.
17. The hoist limiting system of claim 16, wherein the means for
positioning at least a portion of the cable around the hoist drum
in a repeatable manner comprises a groove defined in an exterior
surface of the hoist drum.
18. The hoist limiting system of claim 17, wherein the groove is a
continuous, helical groove extending from the first end of the
hoist drum to the second end.
Description
BACKGROUND
[0001] 1. Field
[0002] This application relates generally to hoist limiting systems
and methods and, more particularly, to systems and methods to limit
a hoist from rotating beyond a desired rotation amount.
[0003] 2. Background Technology
[0004] Hoist and/or winch systems can be used to lift or otherwise
pull a rope or cable. For example, a trailing portion of the cable
can be connected to a hoist drum of a hoist, and a leading portion
of the cable can be connected to an item to be moved, such as, for
example and without limitation, a drill rod from an exploratory
drilling operation. A portion of the cable can be wound around the
hoist drum a desired number of wraps to frictionally engage the
drum and help maintain the connection between the cable and the
hoist drum. The hoist drum can rotate in a first direction to lift
or retrieve the item, and the hoist drum can rotate in a second
direction to lower the item away from the hoist.
[0005] To save time necessary when lifting or lowering the item,
the hoist drum can typically be rotated at a very high speed to
quickly retrieve and return the item. When raising the item, if the
hoist drum over rotates, the item can contact a pulley or other
equipment thereby potentially damaging the item and/or the other
equipment. Similarly, when lowering the item, if the hoist drum
over rotates, the cable can become unwound from the hoist drum.
This can reduce the number of wraps of the cable around the hoist
drum to a level below the desired number of wraps.
[0006] Accordingly, there is a need in the pertinent art for
retrieval systems that limit the rotation of the hoist drum to a
desired rotation amount in both the first and second rotation
directions.
SUMMARY
[0007] Described herein is a hoist limiting system to prevent over
rotation of a hoist or winch. The hoist limiting system can
comprise at least one of a hoist drum, a carrier weldment and at
least one switch.
[0008] In one aspect, the hoist drum can be configured for
selective rotation about a drum rotation axis in a first direction
and an opposed, second direction. In another aspect, a groove can
be defined in at least a portion of an exterior surface of the drum
in a helical pattern such that the groove is a continuous groove
extending from a first end of the hoist drum towards a second end
of the hoist drum. The groove can be sized to correspond to a
diameter of a cable attached to the hoist drum. In use, as the drum
rotates, the groove of the drum can urge the cable to a desired
position around the drum. As can be appreciated, because the hoist
drum diameter is known and because the groove of the hoist drum
urges the cable to the desired position, the length of cable wound
onto or off of the hoist drum can easily be calculated. Further,
because the hoist drum diameter is known and because the groove of
the hoist drum urges the cable to the desired position, each groove
location can correspond to a predetermined length of cable. For
example, if a portion of the cable first contacts the groove of the
drum at a predetermined location between the first and second ends
of the hoist drum, the length of cable required to be wound onto or
off of the hoist drum for the cable to contact that groove location
can be determined.
[0009] In one aspect, the carrier weldment can be positioned
adjacent the hoist drum and can comprise a mounting plate, at least
one cable finger and at least one trigger contacting member. In
this aspect, the mounting plate can be slidably attached to the
hoist such that the mounting plate can slide in a direction
substantially parallel to the hoist drum rotation axis. The at
least one cable finger and at the least one trigger contacting
member can be attached to and extend from the mounting plate.
[0010] The at least one switch can be positioned between the hoist
drum and at least a portion of the carrier weldment, and can be
electrically coupled to the hoist (for example, a motor of the
hoist), to stop or start rotation of the hoist drum.
[0011] In use, rotation of the grooved hoist drum can urge the
cable towards the first or second end of the hoist drum. The at
least one cable finger can be positioned relative to the first
and/or second ends so that the cable contacts that at least one
cable finger when a desired length of cable has been wound onto, or
unwound from, the hoist drum. This contact between the cable and
the at least one cable finger can slide the mounting plate and the
at least one trigger contacting member until the at least one
contacting member actuates the at least one switch. Upon actuation,
the at least one switch can send a signal to the hoist motor,
thereby stopping rotation of the hoist.
[0012] Additional advantages of the invention will be set forth in
part in the description which follows, and in part will be obvious
from the description, or may be learned by practice of the
invention. The advantages of the invention will be realized and
attained by means of the elements and combinations particularly
pointed out in the appended claims. It is to be understood that
both the foregoing general description and the following detailed
description are exemplary and explanatory only and are not
restrictive of the invention, as claimed.
DESCRIPTION OF THE DRAWINGS
[0013] These and other features of the preferred embodiments of the
invention will become more apparent in the detailed description in
which reference is made to the appended drawings wherein:
[0014] FIG. 1 is a side elevational view of a first exemplary hoist
limiting system as described herein.
[0015] FIG. 2 is an exploded perspective view of the hoist limiting
system of FIG. 1.
[0016] FIG. 3 is an assembled perspective view of the hoist
limiting system of FIG. 1.
DETAILED DESCRIPTION
[0017] The present invention can be understood more readily by
reference to the following detailed description, examples,
drawings, and claims, and their previous and following description.
However, before the present devices, systems, and/or methods are
disclosed and described, it is to be understood that this invention
is not limited to the specific devices, systems, and/or methods
disclosed unless otherwise specified, and, as such, can, of course,
vary. It is also to be understood that the terminology used herein
is for the purpose of describing particular aspects only and is not
intended to be limiting.
[0018] The following description of the invention is provided as an
enabling teaching of the invention in its best, currently known
embodiment. To this end, those skilled in the relevant art will
recognize and appreciate that many changes can be made to the
various aspects of the invention described herein, while still
obtaining the beneficial results of the present invention. It will
also be apparent that some of the desired benefits of the present
invention can be obtained by selecting some of the features of the
present invention without utilizing other features. Accordingly,
those who work in the art will recognize that many modifications
and adaptations to the present invention are possible and can even
be desirable in certain circumstances and are a part of the present
invention. Thus, the following description is provided as
illustrative of the principles of the present invention and not in
limitation thereof.
[0019] As used throughout, the singular forms "a," "an" and "the"
include plural referents unless the context clearly dictates
otherwise. Thus, for example, reference to "a hoist" can include
two or more such hoists unless the context indicates otherwise.
[0020] Ranges can be expressed herein as from "about" one
particular value, and/or to "about" another particular value. When
such a range is expressed, another aspect includes from the one
particular value and/or to the other particular value. Similarly,
when values are expressed as approximations, by use of the
antecedent "about," it will be understood that the particular value
forms another aspect. It will be further understood that the
endpoints of each of the ranges are significant both in relation to
the other endpoint, and independently of the other endpoint.
[0021] As used herein, the terms "optional" or "optionally" mean
that the subsequently described event or circumstance may or may
not occur, and that the description includes instances where said
event or circumstance occurs and instances where it does not.
[0022] The word "or" as used herein means any one member of a
particular list and also includes any combination of members of
that list.
[0023] Reference will be made herein to a hoist for use with a
mainline retrieval system. However, it is contemplated that the
hoist limiting systems described here can be used with a hoist or
winch in any application such as, for example, construction hoists,
elevator hoists, automotive winches, and the like. Further, it is
understood that the hoist limiting system of the present
application can be used in any other instances in which a hoist or
winch is required, such as for example and without limitation, a
haul hoist of a drilling system or other non-drilling systems in
which a hoist is used.
[0024] Referring now to FIG. 1, in one aspect, the hoist limiting
system 10 for a hoist 2 can comprise at least one of a hoist drum
12, a carrier weldment 14 and at least one switch 18. As described
more fully below, rotation of the hoist drum can cause a cable
attached to the drum to contact a portion of the carrier weldment,
thereby moving the carrier weldment 14 to actuate the at least one
switch. The at least one switch can be electrically coupled to the
hoist (for example and without limitation, a motor or processor of
the hoist), to stop or start rotation of the hoist. As can be
appreciated, the hoist limiting system can be a kit configured for
retrofitting a conventional hoist that lacks a hoist limiting
system. Alternatively, the hoist limiting system 10 can be a
portion of a hoist 2 having an integrated hoist limiting
system.
[0025] The hoist drum 12 is a drum configured for selective
rotation about a drum rotation axis (i.e., the longitudinal axis of
the drum). In one aspect, the hoist drum can rotate about the drum
rotation axis in a first direction and an opposed, second
direction. In use, a cable 20, wire, rope and the like (referred to
hereinafter only as a "cable" for convenience and clarity) can be
attached to the hoist drum 12 so that rotation in the first
direction winds a portion of the cable onto the hoist drum, and
rotation in the second direction unwinds a portion of the cable 20
from the hoist drum. In another aspect, the hoist drum 12 can have
a drum diameter.
[0026] In one aspect, an exterior surface 22 of the hoist drum 12
can define a groove 24. In another aspect, the groove can be
defined in a helical pattern on the exterior surface of the hoist
drum such that the groove is a continuous groove extending from a
first end 26 of the hoist drum to a second end 28 of the hoist drum
12. In yet another aspect, the groove can have a groove diameter
sized to correspond to a diameter of the cable 20. For example, the
groove diameter can be substantially equal to or slightly larger
than the diameter of the cable so that the cable can be positioned
in the groove. In a further aspect, at least a portion of the
groove 24 can be positioned at an acute angle relative to the drum
rotation axis of the hoist drum 12. In this aspect, as the hoist
drum rotates in the first direction, the cable can be wound onto
the hoist drum and can be positioned in the groove from the first
end of the hoist drum towards the second end. Similarly, as the
hoist drum rotates in the second direction, the cable can be
unwound from the hoist drum 12 from the second end 28 of the hoist
drum towards the first end 26.
[0027] The groove 24 can comprise at least one groove sidewall 30
configured to separate one course of the groove from an adjacent
course of the groove. In one aspect, the groove sidewall can have a
sidewall height corresponding to the diameter of the cable 20. For
example, the groove sidewall can have a sidewall height of about
10%, about 20%, about 25%, about 30%, about 33%, about 40%, about
50%, about 60%, about 67%, about 70%, about 75%, about 80%, about
90%, or about 100% of the diameter of the cable. In another aspect,
the groove sidewall 30 can be positioned at an acute angle relative
to the drum rotation axis of the hoist drum 12. In use, as the
hoist drum rotates, the groove sidewall can urge at least a portion
of the cable into the groove.
[0028] In one aspect, the groove 24 and/or the groove sidewall 30
can position the cable 20 around the hoist drum 12 in an orderly
and/or repeatable manner. For example, the groove and/or the groove
sidewall can position a portion of the cable around the hoist drum
in a first layer of cable that is positioned in the groove. The
sidewall can space the wraps of cable 20 from each other so that a
second layer of cable can be positioned in wraps formed on top of
the first layer in a repeatable manner. This can continue until the
desired length of cable has been positioned on the hoist drum 12.
That is, the cable can be wound onto the hoist drum in the same
manner each time so that the same portion of cable 20 is positioned
in the same location on the hoist drum every time it is wound onto
the hoist drum. Similarly, the cable can be unwound from the hoist
drum 12 in the same manner each time so that the same portion of
cable is positioned in the same location on the hoist drum every
time it is unwound from the hoist drum 12. In another example, the
groove and/or the groove sidewall can position a portion of the
cable around the hoist drum in a first layer of cable that is
positioned in the groove, such that a second layer of cable will
not be positioned in wraps formed on top of the first layer.
[0029] The carrier weldment 14 can be positioned adjacent the hoist
drum 12 and can comprise a mounting plate 32 and at least one axial
rod 34, as illustrated in FIG. 2. In one aspect, the carrier
weldment further comprises a mounting bracket 36. The at least one
axial rod can be securedly attached adjacent the hoist, by for
example, attaching the at least one axial rod 34 to a frame 38 of
the hoist 2. In another example, the mounting bracket 36 can be
securedly attached to the frame of the hoist, and the at least one
axial rod 34 can be securedly attached to the mounting bracket. In
another aspect, the at least one axial rod can be positioned
adjacent the hoist drum 12 such that a rod longitudinal axis is
substantially parallel to the drum rotation axis of the hoist
drum.
[0030] At least a portion of the mounting plate 32 can be slidably
attached to the at least one axial rod 34 so that the mounting
plate can slide along the rod axis. For example, at least a portion
of the mounting plate can surround at least a portion of the axial
rod so that the mounting plate is free to slide along the rod axis.
In one aspect, at least one bushing 39 can be attached to the
mounting plate. In this aspect, the at least one axial rod can be
inserted through the at least one bushing to guide the axial rod 34
along the rod axis. In use then, the mounting plate 32 can be
configured for linear movement substantially parallel to the drum
rotation axis of the hoist drum 12.
[0031] In another aspect, the carrier weldment 14 can further
comprise a means for centering at least a portion of the mounting
plate 32 relative to a center line of the hoist drum 12. For
example, the carrier weldment can comprise a biasing means 40 (such
as, for example and without limitation, a spring) positioned on
opposed ends of the at least one axial rod 34. Each biasing means
can exert approximately the same force on the mounting plate so
that, in the absence of external forces, the mounting plate 32 can
be approximately centered relative to the center line of the hoist
drum 12. Thus, if the biasing means comprises a pair of compressive
springs, the springs can be approximately the same length, and can
each exert approximately the same force on the mounting plate.
[0032] In one aspect, the carrier weldment 14 can further comprise
at least one trigger contacting member 42 attached to and extending
from the mounting plate 32. For example, the at least one trigger
contacting member can be an arm, plate or the like configured to
contact the at least one switch 18 when the mounting plate is in a
predetermined position. In another aspect, the at least one trigger
contacting member 42 can be positioned on the mounting plate such
that when the mounting plate of the carrier weldment is in a
predetermined position, the at least one trigger contacting member
contacts the at least one switch 18. In yet another aspect, the at
least one trigger contacting member 42 can extend away from a first
side 44 of the mounting plate 32 a predetermined distance. For
example, the at least one trigger contacting member can be
positioned such that a longitudinal axis of the trigger contacting
member is substantially normal to the rod axis of the at least one
axial rod 34. In a further aspect, the at least one trigger
contacting member can be adjustably, securedly attachable to the
carrier weldment 14. That is, the at least one trigger contacting
member 42 can be selectively positioned by a user relative to the
mounting plate, so that the mounting plate 32 is in a predetermined
position when the at least one trigger contacting member 42
contacts the at least one switch. For example, the at least one
trigger contacting member can define an adjustment slot so that the
at least one trigger contacting member 42 can selectively be
positioned relative to the mounting plate 32 by a user.
[0033] According to one aspect, the carrier weldment 14 can further
comprise at least one cable finger 16 attached to and extending
therefrom. In one aspect, the at least one cable finger can be
positioned such that a longitudinal axis of the finger is
substantially normal to the rod axis of the at least one axial rod
34. In another aspect, the at least one cable finger can extend
from a second side 46 of the mounting plate 32 a predetermined
distance. As can be appreciated, the first side 44 of the mounting
plate can be opposed to the second side, such that the at least one
trigger contacting member 42 and the at least one cable finger
extend generally away from each other. In a further aspect, at
least one slot 48 can be defined in a portion of the mounting plate
32. In this aspect, the slot can allow the position of the cable
finger 16 to selectively be adjusted relative to the mounting plate
as desired by a user. For example, a rod 50, bolt, screw, pin and
the like could extend through the slot and attach to the at least
one cable finger. A user could move the at least one cable finger
16 relative to the slot 48 to a desired positioned, after which the
rod, bolt, screw, pin and the like could be tightened to securedly
attach and maintain the at least one cable finger in the desired
position.
[0034] In another aspect, the at least one cable finger 16 can be a
substantially cylindrical roller 52. In this aspect, the roller can
be configured for selective rotation about a roller rotation axis.
In a further aspect, the roller rotation axis can be substantially
normal to the drum rotation axis of the hoist drum 12.
[0035] As illustrated in the figures, the at least one cable finger
16 can comprise two cable fingers. In one aspect, a first cable
finger 54 can be spaced from a second cable finger 56 a
predetermined distance. In another aspect, the first cable finger
can be positioned adjacent the first end 26 of the hoist drum 12,
and the second cable finger can be positioned adjacent the second
end 28 of the hoist drum. In another aspect, a bar 58 can couple
the free ends of the ends of the first and second cable fingers
(i.e., the ends of the first and second cable fingers opposed to
the mounting plate 32). In this aspect, as can be appreciated,
portions of the mounting plate, the first and second cable fingers
54, 56 and the bar 58 can form an enclosure through which the cable
can be threaded, as illustrated in FIG. 3.
[0036] The at least one switch 18 can be a toggle switch configured
to send an electrical signal upon actuation by the at least one
trigger contacting member 42. Thus, in one aspect, the at least one
switch can be positioned adjacent to the at least one trigger
contacting member so that, upon movement of the at least one
trigger contacting member 42 in a desired direction, the at least
one switch sends an electrical signal to start, speed up, slow
down, reverse and/or stop the hoist motor. In another aspect, the
at least one switch 18 can comprise two switches. In this aspect, a
first switch can be positioned adjacent to the at least one trigger
contacting member so that, upon movement of the at least one
trigger contacting member 42 in a first direction, the at least one
switch sends a first electrical signal to the hoist motor and a
second switch can be positioned adjacent to the at least one
trigger contacting member so that, upon movement of the at least
one trigger contacting member in a second direction, the at least
one switch 18 sends a second, different electrical signal to the
hoist motor. In still another aspect, the at least one switch can
be a dual switch configured to send a first electrical signal when
contacted from a first side, and a second electrical signal when
contacted from a second side. In this aspect, for example, the dual
switch can send a first electrical signal upon actuation by a first
trigger contacting member and a second electrical signal upon
actuation by a second trigger contacting member.
[0037] To assemble the hoist limiting system 10, the mounting
bracket 36 can be securedly attached to the frame 38 of the hoist
2, and the at least one axial rod 34 can be securedly attached to
the mounting bracket. Alternatively, in one aspect, the at least
one axial rod 34 can be securedly attached to the frame 38 of the
hoist adjacent to the hoist drum 12.
[0038] The at least one axial rod 34 can be positioned such that a
longitudinal axis of the axial rod is substantially parallel to the
drum rotational axis of the hoist drum 12. The mounting plate 32
can be slidably attached to the at least one axial rod. In one
aspect, the mounting plate can be slidably attached to the at least
one axial rod between the biasing means 40. For example, the
mounting plate can be slidably positioned on the axial rod, and the
biasing means can urge the mounting plate to a center, neutral
position.
[0039] The at least one cable finger 16 can be securedly attached
to the mounting plate 32 such that the longitudinal axis of the at
least one cable finger is substantially normal to the drum
rotational axis of the hoist drum 12. In one aspect, the at least
one cable finger can extend away from the second side 46 of the
mounting plate. As will be discussed more fully below, the at least
one cable finger can be positioned on the mounting plate in a
predetermined position to correspond to a desired cable length.
Similarly, the at least one trigger contacting member 42 can be
securedly attached to and extend from the mounting plate 32. For
example, the least one trigger contacting member can extend away
from the first side 44 of the mounting plate.
[0040] The at least one switch 18 can be securedly attached to the
frame 38 of the hoist 2 or to the mounting bracket 36 at a desired
position. In one aspect, at least a portion of the at least one
switch can be positioned between the hoist drum 12 and the mounting
plate 32. In this aspect, as the mounting plate slides along the at
least one axial rod 34, portions of the mounting plate and/or the
at least one trigger contacting member 42 can contact the switch
when the mounting plate and/or the least one trigger contacting
member are in the desired position. In another aspect, the at least
one switch 18 can be electrically coupled to the motor of the hoist
2. For example, the at least one switch can be coupled to a means
for controlling the motor of the hoist, such as a motor controller,
a processor and the like.
[0041] In use, a first end of the cable 20 can be attached to the
hoist drum 12. As can be appreciated, upon rotation of the hoist
drum about the rotation axis in a first direction, the cable can be
at least partially wound around the hoist drum. As the hoist drum
rotates, the cable can be positioned in the groove 24 by the groove
and/or the groove sidewall 30. For example, the cable and the grove
of the hoist drum can be sized so that at least a portion of the
cable 20 can be positioned in the groove. Because the hoist drum
has a drum diameter, each revolution of the hoist drum can
correspond to the known length of cable being wound onto or unwound
from the hoist drum.
[0042] In one aspect, because the groove 24 can be a helical groove
extending from the first end 26 of the hoist drum 12 towards the
second end 28 of the hoist drum, the cable 20 can be at least
partially wound around the hoist drum from the first end towards
the second end of the hoist drum 12. That is, as the cable is wound
onto the hoist drum, the cable 20 can be wound onto the drum at a
changing position on the drum face. In one aspect, the position of
cable 20 being wound onto the hoist drum changes relative to the
first and second ends of the drum as the drum rotates. For example,
when the hoist drum 12 rotates about the rotation axis in the first
direction, the cable can be positioned in the groove 24 such that
each successive portion of the cable is positioned closer to the
second end 28 of the hoist drum that the preceding portion.
Similarly, when the hoist drum rotates about the rotation axis in
the second direction, the cable can be positioned in the groove
such that each successive portion of the cable is positioned closer
to the first end 26 of the hoist drum 12 that the preceding
portion.
[0043] In another aspect, the groove 24 and/or the groove sidewall
30 can position the cable 20 around the hoist drum 12 in an orderly
and/or repeatable manner. That is, the cable can be wound onto the
hoist drum in the same manner each time so that the same portion of
cable is positioned in the same location on the hoist drum every
time it is wound onto the hoist drum 12. Because of this, the
position of a portion of the cable 20 on the hoist drum relative to
the ends of the hoist drum and the longitudinal axis of the hoist
drum can correspond to a cable length. That is, the positioning of
the cable on the hoist drum can be correlated to a length of cable
20 wound onto the hoist drum and a length of cable unwound from the
hoist drum for every position of cable on the hoist drum.
[0044] As the hoist drum 12 rotates and the position of the cable
20 being wound onto the drum changes, a portion of the cable can
contact the at least one cable finger 16. As the drum continues to
rotate, a portion of the cable can exert a sufficient force to
overcome the force exerted on the mounting plate 32 by the biasing
means 40, and the at least one cable finger and the mounting plate
can slide along the at least one axial rod 34 towards the first end
26 or the second end 28 of the hoist drum (depending on the
direction of rotation of the hoist drum). Because the at least one
trigger contacting member 42 can be attached to and extend from the
mounting plate 32, the sliding movement of the at least one cable
finger and mounting plate can slide the at least one trigger
contacting member into contact with the at least one switch 18,
thereby actuating the switch. Upon actuation of the switch, the
switch 18 can send an electrical signal to cause the motor of the
hoist 2 to stop or otherwise alter the rotation speed and/or
direction of the hoist drum 12. For example, upon actuation of the
switch, the switch can send an electrical signal to cause the motor
of the hoist to stop, speed up, slow down, or reverse the rotation
of the hoist drum as desired by the user.
[0045] In one aspect, because the hoist drum 12 has a drum
diameter, the position of the at least one cable finger 16 can be
selected to correspond to a desired length of cable 20. For
example, if the drum diameter is such that the drum face has a
perimeter distance of one foot, and a user of the hoist 2 wants to
stop the hoist after five feet of cable has been wound onto the
hoist drum 12, the at least one cable finger 16 can be positioned
such that after about five revolutions of the hoist drum, portions
of the cable 20 will contact the at least one cable finger, urging
the cable finger 16, the mounting plate 32 and the at least one
trigger contacting member 42 to slide so that the trigger
contacting member contacts the switch 18, thereby stopping the
hoist drum.
[0046] In another example, to stop rotation of the hoist drum 12
with a desired amount of cable extending from the hoist drum, a
user can rotate the hoist drum until the desired amount of cable
has been wound onto or off of the drum. The position of the at
least one cable finger 16 and/or the at least one trigger
contacting member 42 can be set relative to the ends and/or the
longitudinal axis of the hoist drum 12 so that the at least one
cable finger is contacting the cable 20, and the at least one
trigger contacting member 42 is contacting the switch 18. Then, in
subsequent winding or unwinding operations, because the cable is
positioned on the hoist drum 12 in a repeatable manner, every time
the desired amount of cable 20 extends from the hoist drum, the
cable will urge the at least one cable finger 16, the mounting
plate 32 and the at least one trigger contacting member 42 to slide
so that the trigger contacting member contacts the switch, thereby
stopping the hoist drum.
[0047] In another aspect, if the at least one cable finger 16
comprises two cable fingers, the cable fingers can be positioned
around the cable such that the first cable finger 54 is positioned
between the cable 20 and the first end 26 of the hoist drum, and
the second cable finger 56 is positioned between the cable and the
second end 28 of the hoist drum. In this aspect, the rotation of
the hoist drum 12 in the first direction can cause the cable 20 to
contact the first cable finger and slide the first cable finger 54
towards the first end of the drum until the at least one trigger
contacting member 42 contacts the at least one switch 18.
Similarly, the rotation of the hoist drum 12 in the second
direction can cause the cable to contact the second cable finger 56
and slide the second cable finger towards the second end of the
drum until the at least one contacting member contacts the at least
one switch.
[0048] If the at least one switch 18 comprises two switches, the
first switch can send a first electrical signal upon actuation by a
trigger contacting member 42 moving in the first direction, and the
second switch can send a second electrical signal upon actuation by
a trigger contacting member moving in the second direction. If the
at least one switch is a dual switch, the at least one switch 18
can send a first electrical signal upon actuation by a trigger
contacting member moving 42 in the first direction and a second
electrical signal upon actuation by a trigger contacting member
moving in the second direction.
[0049] The methods and systems described above require no
particular component or function. Thus, any described component or
function--despite its advantages--is optional. Also, some or all of
the described components and functions described above can be used
in connection with any number of other suitable components and
functions.
[0050] Although several embodiments of the invention have been
disclosed in the foregoing specification, it is understood by those
skilled in the art that many modifications and other embodiments of
the invention will come to mind to which the invention pertains,
having the benefit of the teaching presented in the foregoing
description and associated drawings. It is thus understood that the
invention is not limited to the specific embodiments disclosed
hereinabove, and that many modifications and other embodiments are
intended to be included within the scope of the appended claims.
Moreover, although specific terms are employed herein, as well as
in the claims which follow, they are used only in a generic and
descriptive sense, and not for the purposes of limiting the
described invention, nor the claims which follow.
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